Intermediate tube guide



J. ,1. REAGAN INTERMEDIATE TUBE GUIDE A ril 28, 1959- 2 Sheets-Sheet 1Filed Dec. 13, I956 INVENTOR. JOHN Jl PEA GAN QZILIW LMJL ATTOENEYS-April 28, 1959 Filed Dec. 15, 1956 J. J. REAGAN 2,883,973

INTERMEDIATE TUBE GUIDE 2 Sheets-Sheet 2 IN V EN TOR.

' JOHN J. REA GA N A wore/v2 X5.

United tates Patent F INTERMEDIATE TUBE GUIDE John J. Reagan, Cleveland,Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, acorporation of Ohio Application December 13, 1956, Serial No. 628,192

6 Claims. (Cl. 122510) This invention relates to improved means forguiding and restraining the tubes of a cylindrical tube heaterintermediate their ends, the latter being supported in conventionalmanner.

I have been particularly concerned with the construction and operationof vertically fired crude oil heaters, used widely today in oilrefineries and reaching considerable heights, to the extent that thetubes thereof are often longer than fifty feet. Such tubes are arrangedin rather close circularly spaced relation adjacent a lining offirebrick or other refractory material and, where positioned and securedonly at the ends, the unsecured lengths are so great that bowing of thetubes under thermal stress is a serious problem. Tubes which bowinwardly or towards the burners become damaged by the flame, whileoutward bowing of the tubes reduces the normal spacing from theinsulating brick liner and, with the correspondingly reduced heattransfer, damage to the brick almost always follows. Bowed tubes alsoare difficult to clean properly in regular maintenance, and it is oftenimpossible to inspect such tubes visually after cleaning to determine ifall the coke has actually been removed.

Certain types of intermediate supports for such tubes have beenproposed, but these have either been wholly ineffective orunsatisfactory for one reason or another. In particular, prior guideshave been prone to mechanical failure, they have been limited forpractical purposes to original construction in requiring an impracticalamount of time and labor for installation in an existing heater, or theyhave been seriously limited with respect to permitting removal andreplacement of tubes in proper maintenance of the heaters.

It is accordingly a principal object of my invention to provide anintermediate tube guide of reliable and durable construction, which iscapable of ready incorporation in existing tube heaters as well as innew construction.

Another object is to provide such a guide which is supported on the tubearray itself, as distinguished from connection to the heater shell. Thelatter arrangement is obviously difficult and expensive to provide in acompleted heater, since the insulating brick in the area where the guideis to be located must be removed to expose the shell for attachment, forexample, by welding, and then replaced.

It is also an object of the invention to provide an intermediate tubeguide which forms an assembly operative to embrace all of the tubes ofthe heater or furnace. Moreover, the new guide permits the removal andreplacement of two of the tubes at one time, this feature furthergreatly simplifying maintenance since heater tubes are usually joined inpairs by welded end return bends.

Another object is to provide a tube guide characterized by the notedadvantageous features which is nevertheless economical to produce andinstall.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related 2,883,973 PatentedApr. 28, 1959 ends, the invention, then comprises the featureshereinafter fully described and particularly pointed out in the claims,the following description and the annexed drawings setting forth indetail certain embodiments of the invention, these being indicative,however, of but a few of the various ways in which the principle of theinvention may be employed.

In said annexed drawings:

Fig. 1 is a transverse sectional view of a vertically fired tube heaterequipped with a tube guide in accordance with the present invention;

Fig. 2 is a perspective view of one section of such guide, the samebeing formed of a plurality of similar sections;

Fig. 3 is a side elevational view of a modified form of guide section;

Fig. 4 is a plan view of this modified section, showing the same asengaged with a number of the tubes;

Fig. 5 is a perspective view of the ends of two further sections inseparated relation preparatory to being interengaged;

Fig. 6 is a further perspective view showing the end sections of Fig. 5as brought together;

Fig. 7 is a section viewed from the plane of the line 7--7 in Fig. 4;and t Fig. 8 illustrates in elevation a tube-carried bracket used forsupport of the guide.

Referring now to the drawings in detail, the vertically fired tubeheater used to illustrate the operative disposition of my new guidecomprises an outer metal shell 10 and a cylindrical wall of insulatingbrick 11 therewithin. The several fluid conducting tubes 12 are arrangedin circularly spaced-apart relation adjacent but out of contact with theinner periphery of the insulating wall. This type of construction iswell known, and further details of the heater are not necessary toappreciate and understand the manner in which the new guide is employed.

The guide, indicated generally by reference numeral 13, is ring-like andof such diameter as to engage the several tubes at the inner side of thearray. It is made up of a plurality of identical arcu-ate sections 14 ofgeneral channel-shaped cross section, shown more clearly by the sectionillustrated in Fig. 2. The flanges 15 formed by the channel are inwardlydirected, and in a line along its outer or base face, each section has anumber of rounded lugs 16 defining, in effect, a scalloped rib whichprovides recesses in which the tubes are engaged by the particularsection in their proper spaced relation.

To accommodate expansion of the guide in operation of the heater, theseveral sections are of such extent that their adjacent ends arenormally separated by gaps 17, with suitable expansion joints connectingthe same. For such purpose, the Fig. 2 section is formed with a pair ofspaced ears 18 projecting from its upper and lower flanges at each end,and such ears are apertured to receive loosely a connecting bar, one ofwhich is shown at 19. It will be clear that each such bar bridges thegap at the section end at which it is located and passes through thelike apertured ears of the adjoining section, the fit being loose forrelative movement of the sections upon expansion.

The guide sections 14 are held laterally against the tubes 12 by meansof U-bolts 20, with each bolt being engaged about one of the tubes andhaving its ends secured to the guide. Certain of the tubes, in variablenumber depending upon the size of the installation, have welded theretosmall clips 21 uniformly positioned to engage beneath the U-boltsassociated With these tubes, and it is in this manner that the guide issupported directly on the tubes at the desired elevation.

The modified form of guide section 22 illustrated in Figs. 3 and 4differs primarily with respect to the type of expansion joint betweenthe adjacent sections of the complete guide. Each section of this typehas a vertical portion 23 provided with recess-defining lugs 24 at itsouter side, similarly as the guide section first described, but contactwith the tubes is here more limited by virtue of the small verticallyextending ribs 25 centrally of the recesses. Thus there is provided anair space 26 about most of the peripheral extent of each tube whichwould otherwise be disposed against the guide. The tubes are againjoined to the guide by U-bolts 27 in the manner previously set forth.

This guide section is further formed with a horizontal portion 28 at theinner side of the vertical portion 23 and extending beyond therespective ends of the latter. At one end 29, the portion 28 isdepressed over a predetermined length, while at the other end 30, it iscorrespondingly off-set upwardly, so that these end portions of adjacentsections in the guide may be overlapped. Such portions are provided withslots 31 adapted in assembly of the complete guide to receive lockedpins or bolts which will hold adjoining ends together while permittingthe sliding shift needed to accommodate expansion.

For increased lateral restraint at the joints, the section ends can beformed as shown in Figs. and 6, with the vertical portions 23' of eachhaving inwardly displaced end lengths 32 and 33 respectively at the topof one section end and at the bottom of the other end. These end lengthsare co-extensive with the horizontal portions 29 and 30', and it will beclear that such construction adds a vertical overlap which precludesrelative lateral movement of the thus interengaged sections.

The support of the guide on the tubes can also be realized by means onthe latter engaged with the guide section body, rather than with theU-bolts attached thereto, and in Fig. 8 I have illustrated such anassembly comprising a bracket 34 welded to tube 12 at the burner side ofthe same and providing a ledge on which the lower margin of the guidesection 22 rests.

It will be seen, however, that all of the sections disclosed constitutein assembled relation an inner, expansible ring guide of unitary nature,which may very conveniently be installed in a tube heater, in numberdepending upon the tube length, service conditions, and the like. In thecase of a vertically fired heater or furnace, such guide is supported bythe tubes, and in all applications, the guide is independent of theheater shell, thereby freeing the same from a certain amount of stresswhich would obtain in a rigid type of shell attachment. Tubes which areonly slightly bowed can be brought into alignment in applying the guidethereto, with the assurance that bowing of all tubes will be eliminatedby the restraining action of the guide.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

1, therefore, particularly point out and distinctly claim as myinvention:

1. In heater construction including an enclosure wall and a plurality ofheating tubes therewithin and spaced therefrom, said tubes extendingvertically in circularly spaced relation with long lengths thereof freeof connection to the enclosure wall, an intermediate guide forsupporting said tube lengths comprising an expansible ring disposedwithin the tube assembly and contacting the inner peripheries of theseveral tubes, means individually securing the tubes to said ring intheir proper spaced-apart relation, and support means carried by atleast certain of the tubes engaged with the guide and supporting thesame at a desired elevation in the assembly, said support means beingthe sole support for said guide.

2. In heater construction including an enclosure wall and a plurality ofheating tubes therewithin, and spaced therefrom, said tubes extendingvertically in circularly spaced relation with long lengths thereof freeof connection to the enclosure wall, an intermediate guide forsupporting said tube lengths comprising an expansible ring disposedwithin the tube assembly and contacting the inner peripheries of theseveral tubes, means carried by said ring defining recesses in which thetubes are seated in their proper spaced relation, means individuallyreleasably securing the tubes laterally to said ring, and support meanscarried by at least certain of the tubes engaged with the guide andsupporting the same at a desired elevation in the assembly, said supportmeans being the sole support for said guide.

3. In a tube heater including an enclosure wall and a cylindrical array.of vertical heating tubes therewithin and spaced therefrom, said tubeshaving long lengths free of connection to the enclosure wall, guidemeans for supporting said tube lengths in predetermined circularlyspaced relation, said guide means comprising a plurality of arcuatesections having their ends interconnected by expansion joints to form anexpansible ring assembly, said sections contacting the tube peripheriesand having spacer means partially embracing the tubes, laterallyextending loop members secured to the sections and respectively engagedabout the tubes, and bracket means carried by certain of the tubes forsupporting the guide means, said bracket means being the sole supportfor said guide means.

4. In a tube heater including an enclosure wall and a cylindrical arrayof vertical heating tubes therewithin and spaced therefrom, said tubeshaving long lengths free of connection to the enclosure wall, guidemeans for supporting said tube lengths in predetermined circularlyspaced relation, said guide means comprising a plurality of arcuatesections having their ends interconnected by expansion joints to form anexpansible ring assembly, laterally extending loop members secured tothe sections and respectively engaged about the tubes, and bracket meanscarried by at least certain of the tubes for supporting the guide means,said bracket means being the sole support for said guide means.

5. In heater construction including an enclosure wall and a plurality ofheating tubes therewithin and spaced therefrom, said heating tubesextending vertically in circularly spaced relation with long lengthsthereof free of connection to the enclosure wall, an intermediate guidefor supporting said tube lengths comprising a plurality of curvedsections arranged and interconnected by expansion means to form a ring,the outer surfaces of said sections defining seats partially embracingthe heating tubes, the tubes being spaced about the ring and extendingaxially with respect thereto, clamping members carried by the sectionsfor securing the tubes to the same, an axially oriented rib in each suchtube seat for reducing the area of contact between the tube and theguide, and support means carried by at least certain of the tubesengaging the guide to support the same at a desired elevation, saidsupport means being the sole support for the guide.

6. In a tube heater including an enclosure wall and a cylindrical arrayof vertical tubes therewithin and spaced therefrom, said tubes havinglong lengths free of connection to the enclosure wall, an intermediateguide for sup porting said tube lengths, said guide comprising anexpansible ring, means clamping the tubes laterally against the ring incircularly spaced relation, and brackets secured to at least some of thetubes providing ledges on which the guide rests, said brackets being thesole support for the guide.

References Cited in the file of this patent UNITED STATES PATENTS1,452,497 Fischer Apr. 24, 1923 1,715,614 Mills June 4, 1929

